IOS

iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple for its iPhone line of smartphones. It was unveiled in January 2007 alongside the first-generation iPhone, and was released in June 2007. Major versions of iOS are released annually; the current stable version, iOS 26, was released to the public on September 15, 2025.

Besides powering iPhone, iOS is the basis for three other operating systems made by Apple: iPadOS, tvOS, and watchOS. iOS formerly also powered iPads until iPadOS was introduced in 2019 and the iPod Touch line of devices until its discontinuation. iOS is the world's second most widely installed mobile operating system, after Android. As of December 2023, Apple's App Store contains more than 3.8 million iOS mobile apps.

iOS is based on macOS. Like macOS, it includes components of the Mach microkernel and FreeBSD. It is a Unix-like operating system. Although some parts of iOS are open source under the Apple Public Source License and other licenses, iOS is proprietary software.

History

In 2005, when Steve Jobs began planning the iPhone, he stated that he had a choice to either "shrink the Mac, which would be an epic feat of engineering, or enlarge the iPod". Jobs favored the former approach but pitted the Macintosh and iPod teams, led by Scott Forstall and Tony Fadell, respectively, against each other in an internal competition, with Forstall winning by creating iPhone OS. The decision enabled the success of the iPhone as a platform for third-party developers: using a well-known desktop operating system as its basis allowed the many third-party Mac developers to write software for the iPhone with minimal retraining. Forstall was also responsible for creating a software development kit for programmers to build iPhone apps, as well as an App Store within iTunes.